1756-En2T Comms

[Armadillo852 25]

Ok all, I feel like an idiot, but for some reason I cannot get this working. I have 2 robot cells, a conveyor cell, and a stretch wrapping cell. The wrapper is using a compact logix. Don't care about that one for now. All others are using a 1756-L61 Rev 17 PLC. With 1756-EN2T rev 2.0 ethernet cards. I am trying to communicate from robot 1 to the conveyors. From robot 2 to the conveyors. Eventually from conveyors to wrapper. I need to use messaging and not produced and consumed tags. Yes I know, I see the eyes rolling and hear the pfff's and sighs. I have my ethernet cable run from robot 1 to conveyors. IP address of robot 1 153.0.0.1 IP address of conveyors 153.0.20.1 PLC's are in slot 0 Ethernet is in slot 1 I added the ethernet cards of the opposite sides to the ethernet tree. It appears that they are communicating because I do not get the yellow triangle. But no data is being passed back and forth. I added the CIP message read and write to the conveyors. I have the comm type set up for rack optimization. But still no data. Any ideas?

[Ken Roach 194]

You only need the 1756-EN2T modules and the Logix CPUs in the I/O tree if you are going to exchange Produced/Consumed Tags. From the perspective of the Robot 1 workcell, the Conveyors workcell is a 'remote' device, so let's use the Robot 1 workcell's perspective. If you are planning to add Produced/Consumed Tags later, delete the remote CPU and the "Rack Optimized" connection to the remote 1756-EN2T, then re-create that connection with a connection type of "None", and add the remote CPU to the I/O tree. If you will never use Produced/Consumed tags, delete the remote 1756-EN2T and the CPU from the I/O tree. Next let's check out the MSG instructions. While having the remote CPU in the I/O tree made selecting the Message Path easy, it's not necessary. The Path should be 1,1, 2,153.0.20.1, 1,0 A MSG instruction is a rising-edge-triggered operation. The pre-conditions on the rung have to go from false to true every time you want a Read or Write to be performed. Post a detailed description of your MSG rung logic, or a screenshot or two, or the *.ACD program. Edited 10 Jun 2010 by Ken Roach

[drforsythe 15]

Sorry if this is too basic, but I notice that the two devices are on different subnets. Is your subnet mask set to 255.255.0.0 in all devices? If not, you may have difficulty communicating across different subnets.